Filter system employing activated carbon, porous material and diatomaceous earth

ABSTRACT

A disposable filter unit for consumer potable water consists of an inner core filled with activated carbon and surrounded by a body of porous material (fiber glass or asbestos) impregnated with diatomaceous earth. An outer layer of diatomaceous earth is formed on the porous material. The direction of water flow is inwardly through the outer materials to the core so that the carbon is arranged downstream of the other filtering materials.

United States Patent Klein 1 Dec. 12, 1972 [541 FILTER SYSTEM EMPLOYING8,219,191 11/1965 Suchy ..2l0/282 x ACTIVATED CARBON, POROUS 3 233 2233/1333 McPhemlmm 9 I D l' t MATERIAL AND DIATOMACEOUS 3,561,602 2/19711421:121 ..2l0/266 EARTH Inventor: Samuel H. Klein, 2240 Halifax Drive,Apt. 1011, Ottawa, Ontario, Canada Filed: Sept. 10, 1971 Appl. No.:179,332

Int. Cl. .;.....B0ld 27/02 1 Field of Search ..2l0/266, 282, 283, 284,315, 210/317 References Cited UNITED STATES PATENTS 5/1927 Hagg..210/282 Primary Examiner-Samih N. Zahama Attorney-Peter Kirby et al.

[5 7] ABSTRACT A disposable filter unit for consumer potable waterconsists of an inner core filled with activated carbon and surrounded bya body of porous material (fiber glass or asbestos) impregnated withdiatomaceous earth. An outerlayer of diatomaceous earth is formed on theporous material. The'direction of water flow is inwardly through theouter materials to the core so that the carbon 'is arranged downstreamof the other filtering materials. 1 1

5 Claims, 3 Drawing Figures PATENTEDuEc 12 me #07- WA TE? supmy 6' 01 0WA 752 su y FILTER SYSTEM EMPLOYING ACTIVATED CARBON, POROUS MATERIALAND DIATOMACEOUS EARTH This invention relates to an improved filterpurification system for use with a water supply. In one example, it isconcerned with a so-called polishing filter, i.e. a filter that is usedafter the conventional filteringplant of a typical municipal watersupply to furnish an additional degree of purity for potable water.

Investigations have shown that the water supplies of major cities today,even after having been through a normal water treatment plant, containmany pollutants that are potentially detrimental to' the health of thosewho drink the water as well as other pollutants that are undesirablefrom the viewpoint of taste and smell.

The pollutants fall mainly into three types:

A. Materials in solution (e.g. insecticides, pesticides and antibiotics;detergents; phenols, lignins and tannins; chlorine compounds; sulphurcompounds including sulphur dioxide and hydrogen sulphide; phosphates;benzidine (which is considered to be a potential cancer-formingcompound); micropollutants (lead, cyanides, radionuclides, chlorinatedhydrocarbons and organic phosphorus pesticides); mutagenic chemicals;and antagonistic (allergy forming) substances.

B. Residual solids, i.e. materials not in solution, but in suspension orin colloidal form (e.g. hydrated oxides of iron, manganese and aluminum;metallic iron and manganese in colloidal form; rust and scale;phosphates and ionized chemicals).

C. Live organisms, such as bacteria, algae and viruses.

It is not intended to suggest that all these pollutants will necessarilyappear in any chosen water sample, but rather that these pollutants ortheir equivalents are each found from time to time in the typical watersup plies of towns and cities in North America and probably in manyother parts of the world. It follows that an ideal polishing filtershould be so constructed as of typical pollutants of each of these threemajor types from water that is destined for drinking or food preparationpurposes.

It is the object of the present invention to provide a filter system ofthis capability. Other objects will appear from the description thatfollows, which description explains one form of filter by way of exampleonly of the invention, and not by way of limitation of the broad scopethereof, such scope being defined in the appended claims. Thedescription that follows should be read in conjunction with theaccompanying drawings, in which:

FIG. 1 is a cut-away side perspective view of a filter device;

FIG. 2 is a cut-away side view of the filter device mounted in a casingto form a filter unit; and

FIG. 3 is a view showing a manner of mounting such a unit beneath akitchen sink or lavatory.

The filter device shown in FIG. 1 consists of an elongate, central coreof stainless steel, perforated by holes 11 and filled with a body ofactivated carbon 12.

' Surrounding the core 10 is a cylindrical body 13 of to be able toeliminate or at least to reduce the amount At one end the core 10 isfixed to a stainless steel or polypropylene flange 15, in the center ofwhich there is t a stainless steel strainer 16 communicating with theinterior of the core 10. The flange is attached to the body 13 by meansof epoxy, preventing the circulation of water between the flange 15 andthe body 13.. At the other end of the unit, a urethane cap 17 surroundsthe end of the body 13 of mineral material and is secured thereto byepoxy or other durable fixing means.

As shown in FIG. 2, this filter device, now collectively designated 20,is mounted by its flange 15 in a cylindrical, water tight housing 21preferably formed of a tough plastic material, but alternatively, ofstainless 15 steel. The housing 21 is closed by a cap 22, and the wholeassembly so formed constitutes a filter unit referred to collectivelyasa unit 23.

When the unit 23 is installed beneath a sink or lavatory, as shown inFIG. 3, inlet and outlet pipes 24, 25

having joints 26, 27 respectively connect the lower and upper ends ofthe interior of the unit 23 through valves 28, 29, to the cold watersupply 30 and thecold faucet 31. The normal connection between theseparts is fitted with a valve 32 which is closed when the valves 28, 29

are open, and vice versa. In this way the cold water the filter devicein a generally radially inward direction.

It is essential to the success of the present invention that theincoming water flow first through the diatomaceous earth before flowingthrough the activated carbon. In other words, the activated carbon mustbe located downstream of the diatomaceous earth. v

The primary effect of the diatomaceous earth is to trap at least some ofthe residual solids and especially the live organisms, e.g. bacteria, inthe incoming water. A body of material of substantial depth, i.e. thematerial 13, impregnated with diatomaceous earth, is necessary in orderto ensure sufficient contact between the diatomaceous earth and theflowing water, which latter must find its way through the many tortuouspaths defined within the material 13. While bacteria will collect tosome extent within the body of material 13, most of the bacteria aretrapped at the layer 14 of diatomaceous earth, and here quickly build upan outer residual solids and the materials in solution, i.e. some of thepollutants A and B above, both in the freshly in-.

coming water and also in the water making its way 5 5 through thematerial 13.

It is important that this action take place upstream of the activatedcarbon to maintain the activated carbon substantially free of bacteriaandresidual solids. The function of the activated carbon is primarily toadsorb organic and micropollution materials in solution, i.e. many ofthe pollutants of type A that are not acted upon by the bio layer. Theability of the activated carbon to properly fulfill this function isreduced if it is exposed to any appreciable degree of blockage to theincoming organisms and residual solids; hence the need to locate theactivated carbon downstream of the diatomaceous earth and mineralmaterial.

Theoretically at least, the physical arrangement of the layers could bereversed, i.e. with the activated carbon on the outside, in which casethe water flow would have to take place in an outward direction, insteadof inwardly.

It will be noted that all the materials used in the filter unit:stainless steel; polypropylene; urethane; activated carbon; the fiberglass or asbestos impregnated layer; and the diatomaceous earth itself,are chemically inert to water, in the sense that they will not dissolvein it.

It is to be observed that the manner of mounting the unit 23 facilitatesits use as a self-contained disposable unit capable of ready removal andreplacement by a new one. The householder or serviceman has merely toclose the valves 28; 29 temporarily and disconnect the joints 26, 27, toreplace a whole new unit 23, the filter device 20 itself being protectedat this time from contamination.

While the example shows the filter unit mounted beneath a domestic sinkinstallation, it will be appreciated that it may be mounted in any otherlocation, domestic, commercial, municipal or industrial where there is aneed to furnish a polishing filtering to a normal water supply toimprove the safety and taste of the water for drinking purposes. In thematter of taste, it may be mentioned that the bacteria that multiply inthe bio layer liberate some carbon dioxide which gives the water aslightly carbonated effect, which is pleasant to the taste,

lclaim:

1. A filter purification system for potable water comprising a. a bodyof activated carbon for adsorption of organic materials in solution inthe water,

b. a body of porous material chemically inert to water for trappingresidual solids in the water, said porous material being diatomaceousearth,

0. means mounting said bodies to cause water requiring to be filtered topass first through said impregnated material and then through theactivated carbon,

(1. and a layer of diatomaceous earth at a surface of said impregnatedmaterial remote from the activated carbon to trap bacteria at said layerand form a bio layer for the bacterial removal of further impuritiesfrom incoming water.

2. A polishing filter device for potable water comprising a. a hollow,elongate, perforated core of rigid material chemically inert to water,

b. a body of activated carbon within said core,

0. a body of porous mineral material chemically inert to watersurrounding said core, said porous material being impregnated withdiatomaceous earth,

. a layer of diatomaceous earth on the outer surface of said impregnatedmaterial,

e. and means for causing water to flow inwardly towards said coresequentially through said layer and said body of porous material, andsubsequently into and along said core in contact with the activatedcarbon therein.

3. A self-contained, disposable filter unit comprising a polishingfilter device according to claim 2 and an elongate, water tight hpusincontaining said filter device, said housing having in et and outletmeans for connecting the unit in a potable water supply to cause thewater therein to flow through said filter device.

4. The invention of claim 2, wherein said porous mineral material isfiber glass.

5. The invention of claim 2, wherein said porous mineral material isasbestos.

impregnated with

2. A polishing filter device for potable water comprising a. a hollow,elongate, perforated core of rigid material chemically inert to water,b. a body of activated carbon within said core, c. a body of porousmineral material chemically inert to water surrounding said core, saidporous material being impregnated with diatomaceous earth, d. a layer ofdiatomaceous earth on the outer surface of said impregnated material, e.and means for causing water to flow inwardly towards said coresequentially through said layer and said body of porous material, andsubsequently into and along said core in contact with the activatedcarbon therein.
 3. A self-contained, disposable filter unit comprising apolishing filter device according to claim 2 and an elongate, watertight housing containing said filter device, said housing having inletand outlet means for connecting the unit in a potable water supply tocause the water therein to flow through said filter device.
 4. Theinvention of claim 2, wherein said porous mineral material is fiberglass.
 5. The invention of claim 2, wherein said porous mineral materialis asbestos.